The following relates generally to wireless communications, and more specifically to handling overlapped uplink transmissions.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communications with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as a Long Term Evolution (LTE) systems or LTE-Advanced (LTE-A) systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipments (UEs).
In some examples of a wireless communications system, a base station and a UE may communicate, for example using uplink (UL) transmissions from the UE to the base station, or downlink (DL) transmissions from the base station to the UE. An uplink transmission, for example, may have some delay between transmission at the UE and reception at the base station. To ensure that reception of various communications at the base station are aligned (compensating for the delay such that transmissions may be aligned), the base station may apply a timing advance (TA) to scheduled transmissions, and may indicate a TA value to various UEs within a geographic coverage area via a TA command. In some cases, UEs within a wireless communications system may be highly mobile, and a TA value corresponding to different devices may become inaccurate as UEs change positions and/or operations. Furthermore, in some examples of a wireless communications system (e.g., a 5G system), wireless nodes within a system may communicate via highly directional beams. For example, a base station and a UE may communicate via beam pair links (BPLs), each BPL including a transmit beam of one wireless node (e.g., a UE) and a receive beam of a second wireless node (e.g., a base station). In some examples, a UE may multiplex various uplink transmissions on more than one BPL. BPLs may be highly directional, and uplink BPLs and downlink BPLs for the same UE may be the same or different. In such a configuration, different BPLs may have different round trip times (RTTs) due to non-reciprocity, or may have different RTTs due to mobility of the UE. Thus, various signals multiplexed by the UE may have different transmissions timings. A first signal and a second signal may overlap, due to the timing misalignment, which may result in collisions and interference at the base station, decreasing performance of the wireless communications system.